View Compilation Error

0_0_17487617_19970.cpp: In function 'void dfs(int)':
0_0_17487617_19970.cpp:33:22: error: 'ui' was not declared in this scope
     for(int i = head[ui != -1;i = edge[i].next){
                      ^
0_0_17487617_19970.cpp:33:30: error: expected ']' before ';' token
     for(int i = head[ui != -1;i = edge[i].next){
                              ^
0_0_17487617_19970.cpp:33:47: error: expected ';' before ')' token
     for(int i = head[ui != -1;i = edge[i].next){
                                               ^